This invention relates to apparatus for use in the production of pellets, such as in a feed pellet mill, and more particularly an apparatus for use in the production of steam and heated water in such a mill.
Typically, a pellet mill has a conditioner, sometimes referred to as a mixer/conditioner, where a selected milled material is conditioned by the addition of heat and/or moisture before it enters the mill die for the production of feed pellets. Steam and heated water have long been used for this purpose. An explanation of the conditioner, and the use of steam and water to condition the milled material, are fully set forth in U.S. Pat. Nos. 3,573,924, 3,932,736, and 4,183,675, the entirities of which are hereby incorporated herein by reference. U.S. Pat. No. 4,183,675 discloses one method and apparatus for generating steam and heated water in a feed pellet mill where a separate steam jacketed heat exchanger is used in the generation of the heated water.
The present invention represents an improvement in heat exchange apparatus for use in the production of pellets, such as in a feed pellet mill, which is very easy and convenient to use and relatively inexpensive, and where the heat exchanger for producing heated water also functions as a steam drop out chamber in the steam generating circuit.
Steam drop out chambers have long been used in the production of steam in a feed pellet mill. One such chamber, or separator, is shown by the reference 66 in FIG. 1 of referenced U.S. Pat. No. 3,932,736. These chambers have generally comprised a generally vertically oriented, cylindrical chamber with a steam inlet at the top, and a steam outlet in the side of the chamber and at right angles to the steam inlet. The portion of the chamber beneath the steam outlet defines a collector for collecting condensate from the steam so that the steam fed from the steam outlet to the conditioner is relatively dry. Another outlet is provided at the lower end of the chamber to feed the collected condensate back to a steam supply. Such drop out chambers have typically been designed with the diameter of the chamber substantially greater than that of the inlet and outlets to aid in separating the condensate out of the steam.
The present invention makes use of this drop out chamber, which typically exists in the circuit for the production of steam to the conditioner of the pellet mill, as also a heat exchanger in the production of heated water for use in the conditioner, such as to add moisture to the milled material.
In accordance with the present invention, a coil, such as of copper, is wound around the outside of the chamber and preferably around about that portion of the chamber beneath the steam outlet defining the trap. The coil is adjustably secured to the chamber so that it may be fastened tightly thereagainst for good heat exchange between the chamber and coil. Water fed through the coil is heated by heat exchange from the chamber, and thereafter fed to the conditioner for conditioning the milled material as desired.
The result is a relatively inexpensive means for producing both steam and heated water for use in a pellet mill, and where the heat exchanger functions not only to produce the heated water, but also as a drop out chamber in the production of steam, thus eliminating the need for a separate steam jacketed heat exchanger for the production of heated water.
These and other objects and advantages of the invention are apparent from the drawing and detailed description to follow.